An observational study in Parkinson Disease, sponsored by University of Exeter. Completed at 4 sites in United Kingdom. Open to participants aged 18 Years to 85 Years. Per ClinicalTrials.gov, last updated 2026-05-18.
Sponsored by University of Exeter · Observational
The purpose of this study is to understand the relationship between problems in sleep, genetic variations in the Aquaporin-4 gene (AQP4), and the development of Parkinson's Disease.
Parkinson's Disease (PD) is a progressive neurodegenerative disease characterized by the abnormal deposition in the brain of aggregates called Lewy Bodies, packed with a protein called α-synuclein. The mechanisms why this protein accumulates in the brain of patients with PD, as well as its relationship with clinical symptoms, is unknown.
Recently, an internal mechanism of drainage of waste proteins called glymphatic system has been identified and characterized. This system is silent during wakefulness and works during sleep. When it is active, a virtual space between the blood capillaries and cells of the brain called astrocytes opens and lets out waste products from the brain. This process is mediated by a protein of the astrocytes called Aquaporin-4 (AQP4). Preclinical studies have shown that the function of this system could be critical for the clearance of β-amyloid, a protein linked with the development of Alzheimer's Disease. Studies in humans have shown that genetic variations some parts of the AQP4 gene, defined as single nucleotide polymorphisms, may increase the likelihood to develop an aggressive form of Alzheimer's Disease. However, no studies in humans have ever been performed in Parkinson's disease and α-synuclein.
In this study, the investigators aim to elucidate whether genetic variations in the AQP4 gene contribute to variations in the clinical presentation and progression of sporadic and genetic forms of Parkinson's disease. To do so, the genetic profile of patients will be determined through a small venous blood sample collection. This will be coupled with clinical and sleep assessment.
4,487 studies on the registry are indexed under Parkinson Disease; 1,082 are open to participants now.
This study's enrollment of 733 is above the median of 96 across 1,057 observational studies indexed under Parkinson Disease.
Browse Parkinson Disease studies →University of Exeter is the lead sponsor of 138 studies on the registry; 25 are open to participants now.
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Patients with a diagnosis of Parkinson's disease according to Published Criteria.
Exclusion Criteria:
Patients with idiopathic or familial Parkinson's disease
Other: Study procedure
All participants will undergo a collection of demographic data, personal and family history for PD, a neurological examination and administration of clinical scales. All participants will undergo a collection of venous blood sample. At the end of the visit they will receive a wristwatch to monitor their sleep at home (Actigraph) and a sleep diary, together with a prepaid envelope to post the watch and the diary back to the investigators. They will also receive a link for a series of online tests for non-motor symptoms related to Parkinson's disease that they can complete remotely at home.
Association between genetic variations in the AQP4 gene and worse motor symptoms in PD patients
The presence of genetic variations in the AQP4 gene, measured with single nucleotide polymorphisms will be correlated, in idiopathic and familial PD patients, with higher (worse) scores on the Hoehn \& Yahr scales
Time frame: Up to 36 months
Association between genetic variations in the AQP4 gene and worse cognitive symptoms in PD patients
The presence of genetic variations in the AQP4 gene, measured with single nucleotide polymorphisms will be correlated, in idiopathic and familial PD patients, with lower (worse) scores on Montreal Cognitive Assessment (MoCA) scale
Time frame: Up to 36 months
Association between genetic variations in the AQP4 gene and worse sleep symptoms in PD patients
The presence of genetic variations in the AQP4 gene, measured with single nucleotide polymorphisms will be correlated, in idiopathic and familial PD patients, with worse sleep performances as assessed with sleep scales and Actigraph
Time frame: Up to 36 months
Association between genetic variations in the AQP4 gene and worse non-motor symptoms in PD patients
The presence of genetic variations in the AQP4 gene, measured with single nucleotide polymorphisms will be correlated, in idiopathic and familial PD patients, with higher (worse) scores on scales for non-motor symptoms.
Time frame: Up to 36 months
Association between genetic variations in the AQP4 gene and altered levels of glymphatic system markers in PD patients
The presence of genetic variations in the AQP4 gene, measured with single nucleotide polymorphisms will be correlated, in idiopathic and familial PD patients, with increased levels of blood concentration of LRP-1, ABCB1 and AQP4
Time frame: Up to completion of study
Association between genetic variations in the AQP4 gene and altered levels of astrocytic
The presence of genetic variations in the AQP4 gene, measured with single nucleotide polymorphisms will be correlated, in idiopathic and familial PD patients, with increased levels of blood concentration of S100β
Time frame: Up to completion of study
Association between genetic variations in the AQP4 gene and altered levels of protein aggregation markers in PD patients
The presence of genetic variations in the AQP4 gene, measured with single nucleotide polymorphisms will be correlated, in idiopathic and familial PD patients, with increased levels of blood concentration of α-synuclein
Time frame: Up to completion of study
Plan to share: No — There is no plan to share IPD with other researchers.
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This study is completed, as verified in Oct 2025. You cannot join it, but the record below documents what was studied.
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University of Exeter